It is well known in the art that, for certain food products, efficiency in packaging and acceptable shelf life can be obtained by hermetically sealing the product in a package in a form/fill/seal (FFS) operation.
In providing a commercially viable package through FFS operations, several considerations must be addressed. One consideration is that the package must be capable of being opened by the consumer without undue difficulty. Another consideration is that the package must be economical to produce, and should be capable of being formed, filled and sealed at relatively high rates. It is also desirable that the package be durable so as to withstand the stresses of the FFS operation and subsequent shipping and handling without damage and without deterioration of appearance.
In recent years, there has been increased demand for zippers or other means to provide reclosability. One particular package configuration that has been used commercially in recent years has a generally rectangular configuration with a reclosable zipper extending within a fold along one edge, as illustrated in, e.g., U.S. Pat. No. 4,589,145. To open the package, the package material may be slit along the folded edge with a knife, scissors, or the like to gain access to the zipper, and the zipper is then opened to provide access to the product. Where each package is to contain a stack of sliced product or a relatively large item such as a block of cheese, the stack or block may be placed on a horizontally-oriented web and the web can be wrapped around the item to form the package as described in the above-referenced U.S. Pat. No. 4,589,145.
When handling products comprised of numerous small pieces such as shredded cheese, cereal, etc., it is generally desirable to have the package partly formed into a pouch which is open at one end, or along one side, with the pouch oriented so that the open end or side is at the top of the partially-formed pouch, and to dispense product into the partially-formed pouch through the open top or side.
Vertical FFS operations such as that described in U.S. Pat. No. 4,874,257 represent one approach to addressing the aforementioned considerations in packaging food products comprised of numerous small pieces. In the method of U.S. Pat. No. 4,874,257, the zipper is disposed vertically along one side of the package being formed, and the pouch is filled by gravity-induced flow of product downward from a filling spout.
Another approach is illustrated by U.S. Pat. No. 4,945,714, in which the pouches travel horizontally as they are formed, filled and sealed. In U.S. Pat. No. 4,945,714, the pouch is formed in an inverted orientation from a single web which has a fold at its lower end and a zipper within the fold. Two potential problems with this approach are that penetration of product into the zipper may occur, and that if the upper end of the pouch is perforated to facilitate opening, or punched to receive a display hanger, loss of hermeticity would result.
One problem that must be addressed in any zipper-equipped package such as those mentioned above is that, where the ends of the zippers extend into seal areas, difficulty may be encountered in providing hermeticity at high throughput rates, due to the increased thickness of the seal area at the ends of the zipper.
As mentioned above, it may be desirable to provide a line of perforation across the pouch adjacent the folded end thereof to facilitate easy opening of the pouch by tearing along the line of perforation. It is important that the line of perforation be straight and continuous, without significant deviation from linearity and with general uniformity in the size and spacing of the perforations to allow for continuous, easy and uninterrupted tearing along the entire width of the pouch. It is also important that the line of perforation be formed in both the front and rear walls of the pouch, with the perforations in the front wall lining up with the perforations in the rear wall. Furthermore, it is desirable to provide such a line of perforation which does not affect the hermeticity of the pouch.
There is a continuing need for improved packages of the type described above, and for improved FFS operations for such packages which address the aforementioned considerations while avoiding the disadvantages of the prior art discussed above.